Workpiece parts lying on a support surface of a punching die at a punching/forming station of a machine tool following processing by severing can be discharged by being pushed through a remaining frame of a workpiece. In some cases, a stripper is provided on a punching tool or a punch of the machine tool. The stripper serves as a guide to aid in pushing the severed workpiece part through the remaining frame of the workpiece. However, the use of a stripper may present problems for formed workpiece parts, because formed features produced on the workpiece part may act as an obstructing contour. Workpiece parts that have formed features (e.g. threaded rim holes, louvers, offsets, beads etc.) may not be reliably discharged, and, therefore, they may remain joined to the (remaining) workpiece by so-called micro joints which may necessitate manual finishing (breaking-off/deburring). Even in the case of workpiece parts not having formed features, pushing the severed workpiece part through the remaining frame of the workpiece can result in a loss of time and low process reliability.
US 2006/0027626 A1 discloses a machine tool on which both forming and processing of a workpiece part by severing can be performed with the use of punching die. A workpiece part joined to a remaining portion of a workpiece via a micro joint is first bent downward at a bending edge of an orifice in the punching die. Then, the micro-joint is positioned at the bending edge and the formed workpiece is severed from the remaining workpiece by a punching operation. The workpiece part severed from the remaining portion of the workpiece is then discharged through the orifice in the punching die. In this case, the size of the workpiece parts to be discharged may be limited to the size of the orifice. The workpiece parts severed from the remaining portion of the workpiece may not fall with a controlled movement and may therefore strike against the edges of the orifice and be damaged.